Valve flow transition

ABSTRACT

A valve construction in which the flow transition region extending from a valve port to the end of the valve body comprises a diffuser section diverging to give cross-sectional area change equivalent to that produced in a cone with an included cone angle of from 6* to less than 20* from the port to a location at or near the end of the body where it terminates in an abrupt discontinuous section which enlarges the flow transition region substantially to the flow area of the conduit to which the valve is connected.

United States Patent Bake [54] VALVE FLOW TRANSITION [72] Inventor: Earl A. Bake, Pittsburgh, Pa.

[73] Assignee: Rockwell Manufacturing Company, Pittsburgh, Pa.

[22] Filed: Mar. 30, 1970 21 Appl.No.: 23,779

Related U.S. Application Data [63] Continuation-in-part of Ser. No. 815,149, Apr. 10,

1969, abandoned.

[52] U.S. Cl ..251/124 [51] Int. Cl ....F16k 5/02, F16k 5/04 [58] FieldotSearch ..251/123,124

[56] References Cited UNITED STATES PATENTS 842,393 1/1907 De Ferranti ....25l/l24 2,717,758 9/1955 Van Deventer ..251/124 Feb. 22, 1972 1,249,601 12/1917 De Ferranti ..25l/124 X 3,085,782 4/1963 Grove ..25 l/ 124 1,112,066 9/1914 Hollis 251/124 X 2,575,464 11/1951 Olsen 251/124 X 2,601,654 6/1952 Wright ....25l/124 X 2,799,467 7/ 1957 Hedene ..25 l/ 124 Primary Examiner-Henry T. Klinksiek Anomey-Strauch, Nolan, Neale, Nies & Kurz [57] ABSTRACT A valve construction in which the flow transition region extending from a valve port to the end of the valve body comprises a diffuser section diverging to give cross-sectional area change equivalent to that produced in a cone with an included cone angle of from 6 0 less than 20 from the port to a location at or near the end of the body where it terminates in an abrupt discontinuous section which enlarges the flow transition region substantially to the flow area of the conduit to which the valve is connected.

18 Claims, 12 Drawing Figures PATENTEDFEB 22 I972 SHEET 1 BF 4 m bbx INVENTOR JMWlWWQMW ATTOR N E Y5 PATENTEBFEBZZ I972 SHEET 2 0F 4 EARL I A. 8/1 KE wfmwwyww I ATTORNEYS PATENTEnreazz I972 3.643.914

' sum 3 or 4 v FIG 70 INVENTOR EARL A. BAKE ATTORN E Y5 VALVE FLOW TRANSITION This application is a continuation-in-part of application Ser. No. 815,149 filed Apr. 10, 1969 for Valve Flow Transition and now abandoned.

BACKGROUND OF THE INVENTION This invention relates generally to valve constructions and more particularly to a novel valve design especially useful in symmetrical valves having ports whose cross-sectional flow areas are significantly less than the flow areas of the connecting pipeline or conduit in which the valve is located. For purposes of the following description a symmetrical valve will be understood to be one which can be placed in a pipeline without regard to the direction of fluid flow and the valve must therefore have the same characteristics for either direction of fluid flow.

1n valves having a flow passage of significantly less crosssectional area than that of the flow line in which they are located, there is a substantial'reduction of fluid pressure in the constricted region. When the constricted passageway thru the valve terminates abruptly at the enlarged cross-sectional area of the pipeline, a modest amount of pressure is recovered but the pressure on the downstream side of the valve is always substantially less than the pressure on the upstream side of the valve, depending on the degree of constriction imposed by the valve.

It has long been known that pressure recovery can be increased and therefore pressure loss across the valve decreased, by gradually increasing, at a relatively low effective angle, the cross-sectional area of the flow passage downstream of the valve closure member, until this gradually enlarging passage merges with the wall of the pipeline. The region in which this gradual increase in area takes place may be referred to as the transition region.

Valve constructions covered by this invention may include types employing circular flow passageways, such as those found in conventional ball or gate valves, as well as types employing noncircular flow passageways, such as the rectangular and trapezoidal cross sections frequently found in plug valves. ln valves with circular flow passageways of cross-sectional area significantly less than the flow area of the connecting pipe, the transition regions may consist of true conical passages, diverging in the direction away from the valve closure member port toward the valve end faces. The shape of such conical transition regions may be defined by stating the included angles of the cone or cones formed by the boundary walls. In valves with noncircular flow passageways, the transition region may vary both in area and in shape along its length to form a fluid passage between the noncircular valve port cross section and the circular cross section of the connecting pipe. For the purpose of achieving the results claimed for this invention, the transition regions in both cases will be defined in terms of an equivalent cone angle which describes the rate of cross-sectional area change with length within the transition region. It will be understood that the term equivalent cone angle in subsequent descriptions as applied to valves with circular passageways will refer to the actual included angle of the cone formed by the boundary walls of the transition regions. As applied to valves with noncircular flow passageways, the term equivalent cone angle will refer to the included angle of an imaginary cone which would produce the same average rate of change in cross-sectional area with length in the transition regions of such valves. For maximum pressure recovery in continuous diffusers, the equivalent cone angle is relatively low, normally between 6 and 10". Use of such small angles requires a relatively long transition region resulting in excessively large and expensive valves or specially constructed diffuser sections downstream of the valve.

One early approach to this problem has been to locate the transition region entirely within the valve body. In existing valve designs, where the available body length for this transition region is adequately long or where the required area change between the valve port and the diameter of the con-' necting pipe is small, a minimum pressure drop is obtainable with conventional transition designs which simply employ a continuously tapered transition region having a small equivalent cone angle permitted by the long available length in the valve body. In such valves, it is known that small equivalent cone angles can be employed in the transition region so that fluid flows readily through the valve without separation from the boundary walls. This type of flow produces a minimum of turbulent vortex action within the valve and in the connecting pipe, and thus produces minimum energy losses in the fluid stream.

In those cases where the required area change between the valve port and the area of the connecting pipeline is large, if the equivalent cone angle of the transition region is sufficiently low to provide maximum pressure recovery, such as shown in U.S. Pat. No. 842,393- to DeFerranti, the valve bodies are often so long and expensive as to make the valves economically impractical. In conventional valves the length available within the valve body for flow transition is limited by such factors as economic considerations, valve design requirements, necessity to adhere to standardized valve lengths and other factors. Therefore, another suggested approach was to provide the entire transition region entirely within the valve body and to use a sufficiently large equivalent cone angle so that at the termination of the transition region, its cross-sectional area was the same as that of the pipeline. This approach is shown, for example, in the Lewis U.S. Pat. No. 2,032,623 and Murnin, Jr. U.S. Pat. No. 2,599,274. It was found, however, that such an approach often results in an equivalent cone angle which is so large that little or no better pressure recovery is realized than in valves having no diffuser section within the body and in which the outlet passage terminates abruptly with a cross-sectional area significantly less than the cross-sectional area of the pipeline.

Other proposals, generally illustrated by the Wolfensperger U.S. Pat. No. 3,005,617, Hedene U.S. Pat. No. 2,799,467, and Van Deventer U.S. Pat. No. 2,747,831 suggested the use of separate, specially constructed diffuser sections which lit internally within the pipeline itself. These proposals have generally been quite successful in operation to minimize pressure drop and promote efficient fluid flow through the valve and pipeline. However, they have been disadvantageous in several respects, in that the specially designed tapered sections are costly, somewhat cumbersome to install, and are not readily manufacturable in standardized lengths, since their effective length is dependent upon the relative size between the flow areas of the valve port and connecting pipe. Further, the benefits of the diffuser are realized only with flow in one preferred direction.

It has been found that by using an equivalent cone angle in the range of 6 to 20 throughout the transition region avai1able within a conventional valve body, and by terminating the transition region abruptly at or near the valve end, the pressure recovery obtained in the transition region plus the pressure recovery obtained at the abrupt enlargement of the fluid passage into the pipeline, results in a total pressure recovery comparable to that obtained by extending the transition area beyond the end of the valve body into the pipe, as taught for example by U.S. Pat. Nos. 2,799,467 and 2,747,831, and provides greatly increased pressure recovery over that available from other prior art attempts to solve the problem as exemplified by U.S. Pat. Nos. 842,393, 2,032,623 and 2,599,274.

It has been observed that the range of optimum equivalent cone angles for discontinuous transition regions as contemplated by this invention is larger (6 to 20) than the range of optimum equivalent cone angles (6 to 10) in a continuous transition region such as shown in U.S. Pat. Nos. 2,799,476 and 2,747,831 because the equivalent cone angle must be balanced against the size of the step produced at the discontinuity at the end of the available transition length.

SUMMARY OF THE INVENTION Accordingly, the primary object of the invention resides in the provision of a novel valve construction for valves in which the port areas are significantly smaller than the connecting pipe areas with the valve construction minimizing fluid pressure and energy losses while maintaining cost and overall valve length within practical limitations.

Another object related to that above resides in the provision of a valve construction employing a novel transition or pressure recovery region extending between the smaller area ports and the larger area connecting conduits, the transition region minimizing pressure losses across the valve while enabling the valve to be constructed with smaller ports, thus providing a lighter, lower cost valve assembly.

Still another object resides in the provision of a novel valve of the above described type including a transition region extending from the smaller area ports to the larger area connecting pipes, the transition region comprising a diffuser flow section extending from the valve ports at an equivalent cone angle of 6 to less than 20, preferably to 14, to a location at or near the end of the valve where it terminates in an abrupt, discontinuous flow section which expands the flow passage substantially to the flow area of the connecting pipe.

A further object resides in the provision of a novel symmetrical valve construction having port areas significantly smaller than the flow areas of the connecting pipe and having relatively short available transition regions between the port areas and connecting pipe wherein the transition regions comprise a diffuser section diverging to give cross-sectional area changes equivalent to an optimum included angle in the range from 6 to less than with a preferred angle generally in the range of 10 to 14, the diffuser section extending from the highvelocity regions nearest the valve port and terminating near or at the end of the valve body in an abrupt discontinuous enlarged section which expands the transition flow area substantially to the flow area of the connecting pipe. Preferably, the boundary walls of the abrupt section are provided with a radius, taper, or blend as is necessary to minimize the flow stream separation when the fluid flow is entering the valve through the transition region and/or as required for structural continuity with other parts of the valve body.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a sectional plan view along line 1-1 of FIG. 2 schematically illustrating the invention as incorporated in a symmetrical reduced port plug valve having circular ports;

FIG. 2 is a sectional view along line 22 of FIG. 1;

FIG. 3 is a partially sectioned end elevation along line 33 of FIG. 2 illustrating the flow diameters of the various circular sections of the plug valve assembly;

FIG. 4 is an enlarged fragmentary section of a flanged end valve illustrating the transition region of the invention including the continuous tapered difr'user section and the abrupt discontinuous enlarged section adjacent the end of the valve body;

FIG. 5 is an enlarged fragmentary section of a flanged end valve similar to FIG. 4 with the abrupt discontinuous section terminating short of the flange end face to provide a recess allowing for casting tolerances;

FIG. 6 is a fragmentary section illustrating the invention incorporated in a valve to be butt welded to its connecting pipe;

FIG. 7 is a section similar to FIG. 6, but showing the valve end socket welded to the connecting pipe;

FIG. 8 illustrates a threaded connection between a valve of the invention and its connecting pipe;

FIG. 9 is a plan section along line 99 of FIG. 10 illustrating the invention as applied to a symmetrical, reduced port, tapered plug valve having noncircular ports;

FIG. 10 is a front elevation section taken along line 10-10 of FIG. 9;

FIG. 11 is an end elevation section taken along line llI1 of FIG. I0; and

FIG. 12 illustrates experimental test results of flow tests comparing circular port valves having conventional continuous transition or pressure recovery regions to valves similar to those illustrated in FIGS. 1 through 3 incorporating the transition regions of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, particularly FIGS. 1-3, the invention is illustrated as incorporated in a symmetrical plug valve having circular ports, the valve having a body 20 with end flanges 22, 24 defining inlet 26 and outlet 28, respectively, and a valve chamber 30 within which plug 32 is rotatably mounted for movement between open and closed positions.

Plug 32 has a circular through-passageway 34 terminating in circular ports 36 and 38 which, in the plug open position, are aligned with respective circular body ports 40 and 42 to permit the passage of fluid through the valve. Coupled to flanges 22 and 24 are respective circular connecting pipes 44 and 46 each of which has an internal diameter D.

The invention is specifically concerned with the configuration of the transition or pressure recovery regions 48 and 50 which extend between the reduced area ports 40 and 42 and the respective inlet 26 and outlet 28. Since the valve illustrated is symmetrical and transition regions 48 and 50 are identical in configuration, only region 50 on the downstream side of the valve will be discussed in detail.

With reference to FIG. 4, illustrating the transition region 50 incorporated in a flanged end valve, transition region 50 comprises a continuous smoothly tapered frustoconical diffuser section A extending from circular port 42 to a location B adjacent the flange end face 25, with section A terminating at location B in rapidly enlarging discontinuous section C, the outermost diameter E of which corresponds substantially to 'the inner diameter D of conduit 46 connected to end flange The included cone angle a of section A lies within the critical range from 6 to less than 20, with the optimum angle generally being in the range of 10 to l4.

Extensive tests have established that with valves embodying an optimum equivalent cone angle throughout the available transition region, the pressure recovery obtained in the transi tion region plus the pressure recovery obtained by the abrupt enlargement of the fluid passageway to the full inside diameter of the pipeline results in a total pressure recovery considerably greater than prior art attempts to confine the transition region within the body of valves. In fact, the total pressure recovery obtained in the valves embodying this invention is comparable to that obtained by employing diffusers embodying the optimum equivalent cone angle and extending into the pipeline a considerable distance.

In general, section A of region 50 should be made as long as possible and should extend to the end of the valve or should terminate in section C at location B as close to the end face 25 as is permitted by practical structural and flow design considerations. Ideally section A on the discharge end of a valve should extend from the port 42 to the end of the valve, even though the area of the outlet passage from the end of the valve would be smaller than the area of the connecting pipe.

In some cases it may be desirable to terminate that part of the transition region having an optimum equivalent cone angle at a point just short of the end of the valve body, at which point it would merge with a relatively rapidly enlarging discontinuous section C as shown in FIGS. 4-8. Such a configuration may be required to facilitate manufacture, welding to the pipeline or in the case of symmetrical valves to minimize flow stream separation when fluid is entering the valve through the transition region. In such valves the direction of fluid flow may be reversed and a transition region according to this invention would be provided on both ends of the valve body. However, use of the optimum equivalent cone angle extending to the outer surface of the inlet flange would cause excessive flow stream separation of the fluid entering the valve. It has been found that this flow stream separation can be minimized by providing suitable boundary wall blending within discontinuous section C.

The equivalent cone angle [3 between the opposite sides of section C lies within the range of 60 to 180, with the actual angle used depending largely on the body length available for the transition region 50. For best results, the boundary walls at location B are provided with a radius or blend as is necessary to minimize flow stream separation when fluid is entering the valve through the transition region and/or as required for structural continuity with other ports of the valve body. The radius r at the intersection of sections A and C, i.e., at point B, preferably lies within the range of zero to D/4. Again however, the actual radius utilized depends upon manufacturing considerations and considerations of stress concentration.

Various other practical considerations may determine the location of points B and E. For example, referring to FIG. 5, section C terminates short of end face 25 to provide an internal recess 52 in flange 24 to allow for casting tolerances.

Similarly, in FIG. 6, section C terminates at point E inwardly of the end face of the valve body to provide counterbore 54 to suit welding requirements for butt welding the end of the valve to its connecting pipe.

Likewise in FIG. 7, where the valve end 56 is to be socket welded to connecting conduit 58, section C terminates inwardly of the valve end at point E to provide counterboro 60 of suitable depth to form a socket weld according to applicable standards.

In FIG. 8, where the valve end 62 is screw connected to pipe 64, section C terminates at point E a distance 66 sufficient to pennit threads to be tapped into end 62.

In symmetrical valve installations and for the various type end connections, the abrupt discontinuous section C terminates in a diameter at location E which is substantially equal to the internal diameter of the pipe to which the valve is connected. In this manner, the transition region 50 includes the smoothly tapered diffusion section A having the desired equivalent cone angle a from 6 to less than 20, preferably 10 to 14, terminating in the abrupt discontinuous section C having an outermost diameter which is substantially equal to the inner diameter of the connecting pipe. This combination of flow sections in the transition or pressure recovery region 50 has been found to represent an optimum compromise of flow efficiency and cost within the practical limitations of overall valve length restrictions. It should be understood however that the benefits of this invention may be realized by terminating the transition region abruptly at flange surface 25 as shown by the dotted lines 50a in FIGS. 4 and 5. In such a case the radius r approaches zero, the angle [3 approaches 180 and the discontinuous section becomes a point or plane of discontinuity.

The invention is readily adaptable for use in valves having noncircular ports. FIGS. 9-11 illustrate a symmetrical valve similar to FIGS. 1-3 but comprising a tapered plug 70 having generally trapezoidal ports which, when the plus is in the open position, register with similar trapezoidal body ports 72 and 74 and transition or pressure recovery regions 76 and 78 which extend from the body ports 72 and 74 to the respective inlet and outlets 80 and 82 of the valve. The included angle between opposed walls defining transition regions 76 and 78 in the horizontal and vertical planes are selected to provide a rate of area increase in the transition section substantially the same as provided in a simple conical section of 6 to less than 20, preferably 10 to 14. The transition regions extend throughout the available transition length at the desired angle, to a point as near as practical to the end of the valve, where the relatively abrupt discontinuity occurs, to enlarge the transition region to substantially the flow area of the connecting pipe.

Although not illustrated, the transition region configuration of the invention may readily be incorporated in other type symmetrical valves, including ball and gate valves, and may also be incorporated in the downstream end of nonsymmetrical valves, such as conventional globe valves.

As noted initially above, in the past it has generally been recognized that the optimum equivalent cone angle is about 10 for diffuser constructions and for valve assemblies incorporating long tubular diffuser extension sections such as those illustrated in the aforementioned Wolfensperger, Hedene, and Van Deventer patents. While systems such as these have generally been very efficient in minimizing fluid pressure losses, they have required long transition lengths because of the substantially continuously tapered flow transition region extending from the smaller valve port area to an end outlet diameter equal to the diameter of the connecting pipe. Because of this, these systems have been impractical for most valve applications and limited in use.

In conventional valves which have not employed these specially designed diffuser sections, but have merely continuously tapered the transition region from the area of the valve port to that of the pipe diameter, the angle of inclination has been excessively high, often 45 or greater, and has produced a highpressure drop through the valve and low overall flow efficiency.

Experimental tests have verified the superior flow characteristics of valves constructed according to the invention over such conventional valves which include a single continuous tapered transition region disposed within the available length of the valve body.

FIG. 12 illustrates the results of certain of these tests employing a circular port valve model having a port flow area equal to 40 percent of the flow area of the connecting pipe. FIG. 12 is a plot of the valve pressure drop coefficient against the included cone angle of the transition region, with the coefficient F being defined by the standard fluid flow equation:

h, Head loss, Feet of fluid flowing v Fluid velocity in pipe, feet/second g Acceleration due to gravity During the tests, the valve length and port length were unchanged, the only variable being the equivalent cone angle a of the transition pressure recovery region, with a transition region having an included angle a=20 representing a conventional continuous transition area tapering uniformly from the smaller valve port to the larger pipe diameter. Models A, B, and C are schematically shown in FIG. 12, with model A representing a valve construction according to the invention as shown in FIG. 4 in which a lies in the range of 6 to less than 20; model B representing a conventional valve having a continuous transition region for which a=20; and model C representing conventional valves having shortened cone transitions in which a is greater than 20.

It is to be noted that for conventional model B, F=0.92 while for model A a minimum of F=0.664 was obtained using a discontinuous transition of the invention with tr-=l2. In other words, the transition configuration of the invention resulted in a pressure drop reduction of about 28 percent when compared to conventional model B.

It is also apparent from FIG. 12 that conventional valves such as model C in which a is greater than 20 produce highpressure drops which cannot be tolerated in efficient fluid systems.

Tests were also performed on an actual circular port valve having conventional uniform continuous transition similar to model B of FIG. 12, with a coefficient F==l .65 being obtained. When the ends of the conventional valve were modified with modeling material to provide a transition region according to the invention similar to model A of FIG. 12 with an included angle a=l4, a coefficient F=0.90 was obtained, this representing a 45 percent reduction in pressure drop over the conventional valve structure.

Similarly, in tests performed on an actual short-pattern, trapezoidal port lubricated plug valve similar to that schematically shown in FIGS. 9-11, a coefficient F. 2.30 was obtained in tests of a valve having standard uniform continuous transitions. However, after the valve ends were modified with modeling material to include transition regions according to the invention, a coefficient E l was obtained, this being a reduction in pressure drop of 50 percent.

Hence, it is apparent that the valve construction according to the invention approaches a valuable, optimum compromise between flow efliciency and cost within the practical limits imposed by valve length restrictions.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of v the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent l. A valve construction having improved pressure recovery in fluid passing therethrough comprising a body having a chamber in which a closure member is movably mounted to control fluid flow between internal ports adjacent said chamber, said body extending between opposite end portions having means for mounting the valve in a fluid conducting conduit of predetermined cross-sectional area, means defining a flow transition passage region extending from at least one of said ports to the adjacent end portion of said body, said transition region comprising a diffuser section having boundary walls which diverge at a predetermined equivalent cone angle substantially in the range from 6 .to 2% from said one port to said one end portion where the diffuser section terminates in an opening smaller than the area of the said conduit and the length of said diffuser section being within a range of substantially from one-fourth to twice the maximum dimension of said one port in either vertical or horizontal section.

2. A valve construction as defined in claim 1, wherein there are similar flow transition regions extending from each port to the associated adjacent end of the body whereby optimum pressure recovery is obtained in either direction of flow through the valve.

3. A valve construction as defined in claim 1, wherein said equivalent cone angle lies in the range of from 10 to 14 4. A valve construction having improved pressure recovery in fluid passing therethrough comprising a body having a chamber in which a closure member is movably mounted to control fluid flow between internal ports adjacent said chamber, said body extending between opposite end portions having means for mounting the valve in a fluid conducting conduit of predeterminedcross-sectional area, means defining a flow transition passage region extending from at least one of said ports to the adjacent end portion of said body, said transition region comprising a diffuser section having boundary walls which diverge at a predetermined equivalent cone angle substantially in the range from 6: to from said one port to a location within said one end portion where the diffuser section terminates in an opening smaller than the area of the said conduit and said transition region then abruptly enlarges to an opening substantially corresponding to the area of said conduit and the length of said diffuser section being within a range of substantially from one-fourth to twice the maximum dimension of said one port in either vertical or horizontal section.

5. A valve construction as defined in claim 4, wherein there are similar flow transition regions extending from each port to the associated adjacent end of the body whereby optimum pressure recovery is obtained in either direction of flow through the valve.

6. A valve construction as defined in claim 4, wherein said equivalent cone angle lies in the range of from 10 to 14c.

7. A valve construction as defined in claim 5, wherein the abrupt enlargement of said transition region is a cone the included an le of which lies in the range of 60 to I 8. A va ve construction as defined in claim 5, wherein the boundary walls of said transition region at said abrupt enlargement curve at a radius of up to D/4, where D is substantially the diameter of the conduit to which the valve is to be connected.

9. A valve construction having improved pressure recovery in fluid passing therethrough comprising a one-piece body having a chamber in which a closure member is movably mounted to control fluid flow between internal ports adjacent said chamber, said body extending between opposite integral end portions having means for mounting'the valve in a fluid conducting conduit of predetermined cross-sectional area, means defining a flow transition passage region extending from at least one of said ports to the adjacent end portion of said body, said transition region comprising a diffuser section having boundary walls which diverge at a predetermined equivalent cone angle substantially in the range from 6 .to 20' from said one port to said one end portion where the diffuser section terminates in an opening smaller than the area of the said conduit.

10. A valve construction as defined in claim 9, wherein there are similar flow transition regions extending from each port to the associated adjacent end of the body whereby optimum pressure recovery is obtained in either direction of flow through the valve.

11. A valve construction as defined in claim 9, wherein the length of said diffuser section is not more than twice the maximum dimension of said one port in either vertical or horizontal section.

12. A valve construction as defined in claim 9, wherein said equivalent cone angle lies in the range of from 10 to 14.

13. A valve construction having improved pressure recovery in fluid passing therethrough comprising a onepiece body having a chamber in which a closure member is movably mounted to control fluid flow between internal ports adjacent said chamber, said body extending between opposite integral end portions having means for mounting the valve in a fluid conducting conduit of predetermined cross-sectional area, means defining a flow transition passage region extending from at least one of said ports to the adjacent end portion of said body, said transition region comprising a diffuser section having boundary walls which diverge at a predetermined equivalent cone angle substantially in the range from 6 to 20' from said one port to a location within said one end portion where the diffuser section terminates in an opening smaller than the area of the said conduit and said transition region then abruptly enlarges to an opening substantially corresponding to the area of said conduit.

14. A valve construction as defined in claim 13, wherein there are similar flow transition regions extending from each port to the associated adjacent end of the body whereby optimum pressure recovery is obtained in either direction of flow through the valve.

15. A valve construction as defined in claim 13, wherein the length of said diffuser section is not more than twice the maximum dimension of said one port in either vertical or horizontal section.

16. A valve construction as defined in claim 13, wherein said equivalent cone angle lies in the range of from 10' to 14a.

17. A valve construction as defined in claim 14, wherein the abrupt enlargement of said transition region is a cone the included angle of which lies in the range of 60 to l8...

18. A valve construction as defined in claim 14, wherein the boundary walls of said transition region at said abrupt enlargement curve at a radius of up to D/4, where D is substantially the diameter of the conduit to which the valve is to be connected.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,643,914 Dated February 22, 1972 Inventor(s) Earl A. Bake It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Line of the Abstract, after 6, change 'o" to --to- Col. 7, line 32, chan e 6' to 20" to 6 to 20--.

line 44, change 10' to 14' to ID" to 14-.

line 56, change 6' to to 6 to 20-. line 70, change 10' to 14' to'-- 10 to 14--.

Col. 8, line 3, chan e 60 ac-180' to --60 to 1ao--..

line 20, change 6' to 20' to --6 to 20 line 33, change 10' to 14' to "16 to 14.

line chan e 6' to 20* to --6 to 2oline 61, change 10 to 14' to --l0 to 14-.

line 64, change to 18' to --60to l-.

Signed and sealed this 11th day of July 1972.

(SEAL) Attest: I

EDWARD M.FLETCHIJR, JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PO-1050 (10- 9) uscoMM-Dc 603764 69 fi' U.S. GOVERNMENT PRINTING OFFICE: I969 O366-334 

1. A valve construction having improvEd pressure recovery in fluid passing therethrough comprising a body having a chamber in which a closure member is movably mounted to control fluid flow between internal ports adjacent said chamber, said body extending between opposite end portions having means for mounting the valve in a fluid conducting conduit of predetermined cross-sectional area, means defining a flow transition passage region extending from at least one of said ports to the adjacent end portion of said body, said transition region comprising a diffuser section having boundary walls which diverge at a predetermined equivalent cone angle substantially in the range from 6* to 20* from said one port to said one end portion where the diffuser section terminates in an opening smaller than the area of the said conduit and the length of said diffuser section being within a range of substantially from one-fourth to twice the maximum dimension of said one port in either vertical or horizontal section.
 2. A valve construction as defined in claim 1, wherein there are similar flow transition regions extending from each port to the associated adjacent end of the body whereby optimum pressure recovery is obtained in either direction of flow through the valve.
 3. A valve construction as defined in claim 1, wherein said equivalent cone angle lies in the range of from 10* to 14*.
 4. A valve construction having improved pressure recovery in fluid passing therethrough comprising a body having a chamber in which a closure member is movably mounted to control fluid flow between internal ports adjacent said chamber, said body extending between opposite end portions having means for mounting the valve in a fluid conducting conduit of predetermined cross-sectional area, means defining a flow transition passage region extending from at least one of said ports to the adjacent end portion of said body, said transition region comprising a diffuser section having boundary walls which diverge at a predetermined equivalent cone angle substantially in the range from 6* to 20* from said one port to a location within said one end portion where the diffuser section terminates in an opening smaller than the area of the said conduit and said transition region then abruptly enlarges to an opening substantially corresponding to the area of said conduit and the length of said diffuser section being within a range of substantially from one-fourth to twice the maximum dimension of said one port in either vertical or horizontal section.
 5. A valve construction as defined in claim 4, wherein there are similar flow transition regions extending from each port to the associated adjacent end of the body whereby optimum pressure recovery is obtained in either direction of flow through the valve.
 6. A valve construction as defined in claim 4, wherein said equivalent cone angle lies in the range of from 10* to 14*.
 7. A valve construction as defined in claim 5, wherein the abrupt enlargement of said transition region is a cone the included angle of which lies in the range of 60* to 180*.
 8. A valve construction as defined in claim 5, wherein the boundary walls of said transition region at said abrupt enlargement curve at a radius of up to D/4, where D is substantially the diameter of the conduit to which the valve is to be connected.
 9. A valve construction having improved pressure recovery in fluid passing therethrough comprising a one-piece body having a chamber in which a closure member is movably mounted to control fluid flow between internal ports adjacent said chamber, said body extending between opposite integral end portions having means for mounting the valve in a fluid conducting conduit of predetermined cross-sectional area, means defining a flow transition passage region extending from at least one of said ports to the adjacent end portion of said body, said transition region comprising a diffuser section having boundary Walls which diverge at a predetermined equivalent cone angle substantially in the range from 6* to 20* from said one port to said one end portion where the diffuser section terminates in an opening smaller than the area of the said conduit.
 10. A valve construction as defined in claim 9, wherein there are similar flow transition regions extending from each port to the associated adjacent end of the body whereby optimum pressure recovery is obtained in either direction of flow through the valve.
 11. A valve construction as defined in claim 9, wherein the length of said diffuser section is not more than twice the maximum dimension of said one port in either vertical or horizontal section.
 12. A valve construction as defined in claim 9, wherein said equivalent cone angle lies in the range of from 10* to 14*.
 13. A valve construction having improved pressure recovery in fluid passing therethrough comprising a one-piece body having a chamber in which a closure member is movably mounted to control fluid flow between internal ports adjacent said chamber, said body extending between opposite integral end portions having means for mounting the valve in a fluid conducting conduit of predetermined cross-sectional area, means defining a flow transition passage region extending from at least one of said ports to the adjacent end portion of said body, said transition region comprising a diffuser section having boundary walls which diverge at a predetermined equivalent cone angle substantially in the range from 6* to 20* from said one port to a location within said one end portion where the diffuser section terminates in an opening smaller than the area of the said conduit and said transition region then abruptly enlarges to an opening substantially corresponding to the area of said conduit.
 14. A valve construction as defined in claim 13, wherein there are similar flow transition regions extending from each port to the associated adjacent end of the body whereby optimum pressure recovery is obtained in either direction of flow through the valve.
 15. A valve construction as defined in claim 13, wherein the length of said diffuser section is not more than twice the maximum dimension of said one port in either vertical or horizontal section.
 16. A valve construction as defined in claim 13, wherein said equivalent cone angle lies in the range of from 10* to 14*.
 17. A valve construction as defined in claim 14, wherein the abrupt enlargement of said transition region is a cone the included angle of which lies in the range of 60* to 18*.
 18. A valve construction as defined in claim 14, wherein the boundary walls of said transition region at said abrupt enlargement curve at a radius of up to D/4, where D is substantially the diameter of the conduit to which the valve is to be connected. 